Cosmic: Always rolls a 10 (+xx%)

[munin]

Originally Posted by Anders

…On the other, you can get a Margin Of Success greater than 0…

You can get a margin of success greater than 0 with normal NDRR, you're just guaranteed at least MoS zero:

"If your ability’s effectiveness is based on your margin of success (e.g., Maledictions, Mind Reading), roll anyway to determine that margin; if you fail, treat it as success with a margin of 0." (Power-Ups 6, p. 8)

It's not an automatic "Take 3", but it still allows margin of success. A "Take 10" mechanic allows you to plan on guaranteed margins, but you still need to work to get them (getting close to your foe to reduce ranged penalties, seeking advantageous conditions, etc.).

Originally Posted by Anders

…you always rolls a 10…

Literally? You can't choose to attempt something more difficult by rolling? Then this means easier things are guaranteed but harder things are impossible (where they might not be impossible if you could try a roll). That's a drawback because not being able to try difficult things when the chips are down is narratively less interesting.

Another enhancement to compare it to is "Stable Casting, +40%" (Thuamatology, pp. 28-29) which makes critical failures much less likely, whereas "Take 10" makes them impossible.

Overall, I'd call "Must Take 10" a +50% enhancement.